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Leaking Shut-Off Valve: What to Do Now and How to Fix It

By / October 22, 2026

If a shut-off valve is leaking, stop the water first and diagnose second. Close the nearest working valve, or the main shutoff for your home, confirm the flow has stopped, and then work out whether the valve is leaking at the handle, at the pipe connection, or through the seat. Most leaks come from a worn packing seal or a tired supply valve that can be repaired or replaced in a single visit. A leak on a gas line is different and is not a do-it-yourself job.

This guide walks you through the emergency steps, how to read what the leak is telling you, when a repair is enough, what permits may apply in Orange County and Los Angeles County, and when to call us.

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TL;DR

  • Shut the water off at the nearest working valve or your main shutoff, then open a faucet to relieve pressure. Do not force a stuck valve.
  • Where the water appears tells you the cause: at the handle usually means worn packing, at the pipe joint usually means a failing connection, and water still flowing when closed means a worn internal seat.
  • Old multi-turn valves often fail after being moved. Replacing the valve is frequently the more durable choice.
  • If the leaking valve is on a gas line or gas appliance, do not touch it. Leave the home and call SoCalGas at 1-800-427-2200 or 911 from a safe place.
  • Replacement, relocation or added piping can require a permit, depending on your city and the scope of work.

Table of Contents

Stop the water first

The fastest way to limit damage is not to identify the exact failed seal. It is to shut off the nearest safe valve you control and check that the flow stops. Water-district guidance such as the Lake Arrowhead Community Services District’s emergency steps follows the same order: find the source, close the fixture valve, and move to the main shutoff if the leak continues.

Here is the sequence we recommend:

  1. Close the leaking valve itself. Turn a wheel or knob handle clockwise until it is snug. A lever handle is usually a ball valve and closes with a quarter turn, so the lever sits perpendicular to the pipe. Stop when it resists. Forcing it can break the stem.
  2. If the leak continues or the handle will not move, close the next valve upstream. For a sink or toilet, that may be a second valve on the same line. Otherwise go to the main shutoff for the house.
  3. Drain residual water. After the water is off, open a faucet at the lowest and highest points and flush a toilet. This relieves pressure in the line, which is a step also recommended in Portland’s emergency shut-off guidance.
  4. Photograph the damage before cleanup. If you rent out the home or may file an insurance claim, dated photos of the valve, the water and any damaged cabinets or flooring help later.
  5. Dry the area. Towels, a wet vac and a fan keep a small leak from turning into mold or swollen cabinetry.

Where your shutoff valves are

Common locations include under sinks, behind or above washing machines, near toilets and water heaters, and where the main line enters the house or sits near the meter. The San Francisco Public Utilities Commission explains the handle difference: wheel handles are typically gate valves that need several turns, while levers are ball valves built to close with a quarter turn.

The exact location depends on when your home was built. Older houses and some apartments have no accessible main shutoff at all, which is worth knowing before an emergency rather than during one.

Which valve is yours to operate

Ownership matters. A valve on your side of the meter is generally your responsibility. A valve that belongs to the utility or water district is a different matter. The Western Municipal Water District’s quick guide warns that turning a district valve the wrong way can damage it. If the only valve you can find is at the meter or curb and you are not sure it is yours, call your water provider instead of using a wrench on it.

What the leak is telling you

Where the water shows up points to the cause. Take a minute with a dry paper towel and wrap it around each part of the valve in turn.

Where it leaks Most likely cause Typical remedy
Under the handle, around the stem Worn or loose packing nut or packing material Light adjustment of the packing nut, or a valve rebuild or replacement
At the pipe or supply line connection Loose compression nut, worn ferrule or washer, corroded fitting Reseat or replace the connection, or replace the valve
Dripping from the faucet or fixture even though the valve is closed Worn internal seat or washer, or mineral buildup Replace the valve
Starts leaking right after you turn it Valve that has not been operated in years and the seal has dried or hardened Replace the valve
Spray or steady flow from the valve body Cracked body, corrosion or a failed fitting Shut off upstream and replace

A shut-off valve that starts dripping immediately after you operate it is often leaking at the stem and packing area rather than at the pipe connection. That is common on valves that sat untouched for years. Turning them breaks the seal that mineral deposits had been holding in place.

Leaking when open, leaking when closed

These are two different failures.

Leaks when the valve is open usually involves the packing around the stem. The packing nut sits just below the handle on a gate-style valve and compresses the packing material. Sometimes an eighth of a turn with a wrench, while a second wrench holds the valve body steady, stops a slow weep. Support the body so you do not twist the pipe or put stress on a soldered joint behind the wall. If a small adjustment does not stop it, the packing is worn out.

Leaks when the valve is closed, or water that keeps flowing after you shut it, usually points to the internal seat or washer. Tightening harder will not fix it and can make it worse. At that point the valve is no longer doing its job, and replacing it is the reliable fix.

Comparison of open and closed valve leaks

Repair or replace

A lot of search traffic on this topic asks the same question: is it better to repair or replace a shut-off valve? Our rule of thumb is simple.

Repair makes sense when:

  • The valve is relatively new and the leak is only at the packing nut.
  • The handle turns freely and the valve shuts off completely.
  • The body and pipe around it show no corrosion.

Replace when:

  • The valve is old multi-turn gate or compression style and drips after being operated.
  • You see green or white crusting, pitting or rust on the body.
  • The valve does not fully stop the flow when closed.
  • You are already replacing a faucet, toilet, or supply lines. The valve is the cheapest part of that job to renew, and it prevents a second call later.

We generally lean toward replacing old valves with quarter-turn ball-style stops. They close with a short, definite motion, which makes them less likely to be forced, and they are easier for a homeowner to operate in an emergency.

A rebuild kit exists for some valves, and it can work on a good-quality valve with a sound body. On a worn-out budget stop under a sink, though, the time and risk of the rebuild often exceed the benefit of a new valve.

Why not just keep tightening

Overstressing a leaking valve is the most common way a small drip becomes a flood. Extra force on the handle can snap the stem or crack the body. Extra force on the compression nut can crush the ferrule or kink the supply line. If a quarter turn of adjustment does not work, stop and shut the water off upstream.

A homeowner’s careful approach to a simple leak

If the leak is a slow weep at the packing nut of an exposed valve, and you are comfortable with basic tools, this is the cautious order:

  1. Close the upstream valve or the main, and open the faucet to release pressure.
  2. Put a towel and a small bucket under the valve.
  3. Use two wrenches: one holding the valve body, one on the packing nut. Turn the packing nut a small amount, about an eighth of a turn.
  4. Restore water slowly and watch the valve for several minutes, then check again after an hour.
  5. If it still weeps, or you notice corrosion, stop. Close the water and replace the valve.

A few situations are not suitable for DIY at all: a valve behind a finished wall, a main shutoff, a valve soldered into copper that needs a torch, or any valve you cannot isolate. Call a licensed plumber for those.

If the leaking valve is on a gas line

A gas shutoff is not a plumbing repair you try yourself. If the leaking valve is on a natural-gas appliance or gas line, do not tighten fittings and do not try to replace it. Gas can ignite from an ordinary spark, including a light switch or a phone.

If you smell gas or suspect a leak, SoCalGas advises that you leave the area and call from a safe location, at 1-800-427-2200 or 911. Avoid switches, flames and anything that could spark. Once the utility has made the situation safe, a licensed professional should handle any gas-piping work.

For background on warning signs, our guides on how to detect gas leaks and gas safety at home are worth reading before you ever need them. If a gas appliance such as a range or oven has a leaking connection, our gas appliance repair team handles the diagnosis and repair once the utility has cleared the area.

If the leaking valve is on a gas line — overview diagram

Not every leaking valve is a supply stop under a sink. A few others come up often:

Permits in Orange County and Los Angeles County

Most homeowners never think about a permit for a valve, and for a simple repair that is often fine. The rules depend on the city and on what exactly gets done.

The City of Los Angeles plumbing code, in Article 4 of the municipal code, requires permits for plumbing work in general but exempts certain minor work, including repair or replacement of exposed shutoff valves and some leak repairs where fixtures or drainage piping are not removed. Broader alterations, new branches, relocation, concealed piping or gas work typically are not exempt.

For unincorporated Los Angeles County, Building and Safety’s plumbing plan-check page lists what needs full plan check, such as a new water service or a new branch of 2 inches or larger. California is also moving through a code cycle: the 2025 California Building Standards Code took effect on January 1, 2026.

Orange County cities each run their own building departments, so confirm with yours before replacement or rerouting work. If you manage rental property, ask your plumber to state in writing which jurisdiction applies and whether a permit was needed or pulled. That protects you if a leak ever turns into a claim.

Questions to ask before you hire a plumber

Whether you call us or anyone else, these questions separate a clear quote from a vague one:

  • Is the technician licensed, and can they tell you their license information?
  • Will you quote the price before work starts, including the valve, labor and any access work such as opening a cabinet back?
  • What type of valve will go in, and what is it connected to (copper, PEX, CPVC, galvanized)?
  • Does the job need a permit in my city, and who handles it?
  • Will the work be tested for leaks before they leave, and is it covered by a guarantee?

Price depends mostly on access rather than on the valve itself. A stop under an open sink cabinet is a short job. A main shutoff in a crawl space or behind a finished wall takes longer. We confirm scope and price before we begin, and we do not publish a flat rate because the job varies that much.

Our perspective on leaking shutoff valves

We see the same pattern again and again in Orange County and Los Angeles County homes. A valve that has not been turned for ten or twenty years gets closed once during a faucet or toilet swap, and it begins to drip. The homeowner tightens it, the stem or nut gives, and the call comes in as an emergency. In most of those cases the valve was already at the end of its life, and replacing it at the start would have cost less than the water damage.

Our advice is practical. Know where your main shutoff is, and test it once a year so you find out it sticks on a calm afternoon. Replace the stops under sinks and toilets whenever a fixture is replaced. Keep gas and water separate in your mind: water you can often manage, gas you leave to the utility and a licensed technician.

We also like to be straightforward about when not to repair. If the valve is corroded, if the pipe behind it looks weak, or if the leak keeps coming back, a proper replacement is the safer job and the better value over time. Our technicians are licensed and experienced, we aim to respond quickly, and we work toward long-lasting fixes that stand behind our guarantee.

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When to call MDTech Services

Call us when the leak will not stop, when the valve is old, stuck or corroded, when the valve is behind a wall or on a main line, or when you are not sure which valve you are looking at. We provide plumbing repair across Orange County and Los Angeles County, with online appointment booking and 24/7 emergency availability. If the leak involves a gas appliance, the gas appliance repair page explains how we handle it.

Landlords and property managers can use the same service to get a written scope and permit status for each job. See our plumbing emergency checklist to prepare before the next leak.

FAQ

How do I get a shut-off valve to stop leaking?

First shut the water off upstream and release the pressure by opening a faucet. If the leak is at the stem, a small adjustment of the packing nut, about an eighth of a turn with a second wrench holding the valve, sometimes stops it. If the valve leaks at the connection or when closed, replacing it is the lasting fix.

Why is my shut-off valve still letting water through when it is closed?

The internal seat or washer is usually worn, or mineral deposits are keeping it from sealing. Turning the handle harder will not help and can break the stem. Close the next valve upstream and replace the leaking one.

Is it better to repair or replace a shut-off valve?

Repair is reasonable for a newer valve with a minor packing leak. Replace an older valve that drips after being turned, shows corrosion, or will not shut off fully. Replacing the valve during a faucet or toilet change is usually the sensible time.

Can I fix a leaking shut-off valve on a gas line myself?

No. Do not tighten or replace gas fittings. If you smell gas, leave the home, avoid switches and flames, and call SoCalGas at 1-800-427-2200 or 911 from a safe distance. A licensed professional should handle any later gas-piping work.

Do I need a permit to replace a shut-off valve?

It depends on your city and the scope. The City of Los Angeles exempts repair or replacement of exposed shutoff valves in some cases, while broader alterations, new branches or gas work generally need a permit. Check with your local building department before replacement or rerouting work.

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